水分胁迫和种植方式对小麦叶绿素荧光参数及水分利用效率的影响

采用不同种植方式,对长武135(A,新品种)和平凉40(B,较老的品种)2个冬小麦品种在拔节到成熟期进行了水分处理,用Image-PAM调制叶绿素荧光仪测定其荧光动力学参数。结果表明,单种方式下,抗旱性较弱、根系过大的B品种在水分胁迫下,其最大荧光产量(Fm)、可变荧光(Fv)、PSⅡ最大光化学量子产量(Fv/Fm)、PS Ⅱ潜在活性(Fv/Fv)、非光化学猝灭(qN)和光化学猝灭(qP)均显著下降,而A品种除qN外,其余指标均无明显变化;干旱胁迫及混种方式下,抗旱性较强、根系相对较小的A品种则呈相反的变化,其Fm,Fv,Fv/Fm,Fv/Fv,qN和 qP均显著下降。分析认为,在单种方式及旱作条件下,根系过大品种的个体间竞争激烈,其群体抗旱性较差,而根系相对较小的A品种个体间竞争弱或无竞争,故群体的抗旱性较强;混种方式和旱作条件下,A品种受到B品种的水分竞争压力,导致干旱胁迫加剧。不同种植方式下,A品种水分利用效率明显较高。

Effect of water stress on chlorophyll fluorescence parameters and WUE of wheat under different planting models

The chlorophyll fluorescence kinetics parameters of two varieties of wheat (A,a new variety; and B,an old variety) that were dealt with water stress in single seeding and mixed seeding were measured in its anthesis by Imaging-PAM chlorophyll fluorometer in this study. The result showed that under water stress,the Fm,Fv,Fv/Fm,Fv/Fv,qN and qP of the B cultivars with weak drought-resistance and relative excessive roots were decreased dramatically,but there were no obvious changes in those parameters of A under the condition of single planting model. But under the condition of mixed planting model the parameters of cultivars with strong resistance and lesser roots decreased obviously contrary to B. The WUE (water utilization efficiency) of A increased obviously under two planting models. The result indicates that with water as dominant factor in the dry land,under the single planting model,the cultivar with excessive roots faces the drastic competition of inter-individual, so the drought-resistance of colony is relatively weak, whereas the cultivar with lesser roots have a relatively weak or even no competition of inter-individual and the drought-resistance of colony is strong. The stress is severe when the cultivar with lesser roots suffers the water competitive stress from the cultivar with excessive roots under mixed planting model. Therefore,it is our aim to choose and cultivate the cultivar with lesser roots and higher WUE in the future.